state Newton law of cooling ,,,,
Answers
Answer:
Newton's law of cooling (or heating) states that the temperature of a body changes at a rate proportional to the difference in temperature between the body and its surroundings
Explanation:
Newton's Law of Cooling
Isaac Newton created his revolutionary Law of Cooling in the 17th century. Newton's Law of Cooling is a formula that allows us to determine the temperature of an object during heat loss. Isaac Newton stated that ¨the rate at which a warm body cools is proportional to the difference between the temperature of the warm body and the temperature of its environment.¨ Newton's theory can also be put into an equation, giving us the Law of Cooling equation:
Law of Cooling
With T (t) being the temperature of an object at a certain time
"t" is the time in seconds
"Ts" is the temperature of the surroundings
"T0" is the starting temperature of the object
and "k" is the cooling constant.
Using this equation, we can calculate how fast an object at a certain temperature would cool in a specific environment, and how the rate of cooling of an object is dependent on the difference of temperature between the object and the surroundings but also on the cooling constant of the object.
Experimental Verification
It is relatively easy to experimentally verify Newton's Law of Cooling. As mentioned above, the Law of Cooling states that ¨the rate at which a warm body cools is proportional to the difference between the temperature of the warm body and the temperature of its environment.¨ We can experimentally verify this law with a spherical calorimeter (a laboratory device that is used to measure the quantity of heat transferred to or from an object) filled with hot water. The calorimeter has mass m and specific heat capacity s and the hot water has mass m1 and specific heat capacity s1. Using the calorimeter we measure the amount of heat energy lost as the temperature of the water and calorimeter falls from temperature T0 to temperature T1 after a set time. As the temperature drops, the temperature is noted for every 30 seconds for a set time. Graphing the change of temperature versus the change in time gives us a cooling curve that we can use to calculate the rate of cooling.
After calculating the rate of the cooling curve, we find that the rate of cooling is proportional to the difference between the temperature of the object and the temperature of the surroundings, verifying Newton's Law of Cooling.
Example 1
You just bought a boiling cup of coffee of temperature 90 degrees celsius. What would be the temperature of the coffee if you let it cool for 2 minutes? The surrounding temperature is 25 degrees celsius and the cooling constant of the coffee is 0.015 1/s.